Answer:
Option (D) is correct.
Explanation:
The balloon lands horizontally at a distance of 420 m from a point where it as released.
Velocity of air balloon along +X axis =10 m/s
velocity of ball=4 m/s along + X axis
the velocity of balloon gets added to the velocity of ball. So the resultant velocity of the balloon=10+4 = 14 m/s
time taken= 30 s
The distance traveled is given by d= v t
d= 14 (30)
d= 420 m
Thus the balloon lands horizontally at a distance of 420 m from a point where it as released.
Explanation:
Given that,
Initial speed of cells is 0 as they were at rest
The acceleration of the cell, 
Time, t = 700 ns
We need to find the maximum speed reached by the cells and the distance traveled during the acceleration. Let v is the final speed. So,

Let d is the distance traveled. Using equation of motion as follows :

Hence, this is the required solution.
Answer:
The speed and direction of the apple is 1.448 m/s and 66.65°.
Explanation:
Given that,
Mass of apple = 0.110 kg
Speed = 1.13 m/s
Mass of orange = 0.150 kg
Speed = 1.25 m/s
Suppose we find the final speed and direction of the apple in this case
Using conservation of momentum:
Before:
In x direction,



In y direction = 0
After:
is velocity of the apple in the y direction
is the velocity of the apple in the x direction
Momentum again:
In x direction,



In y-direction,



We need to calculate the speed of apple

Put the value into the formula


We need to calculate the direction of the apple
Using formula of angle

Put the value into the formula


Hence, The speed and direction of the apple is 1.448 m/s and 66.65°.
Answer:
Few millimeter thick aluminium, water, wood, acrylic glass or plastic.
Explanation:
The materials that are best for protection against beta particles are few millimeter thickness of aluminium, but for the high energy beta-particles radiations the low atomic mass materials such as plastic, wood, water and acrylic glass can be used.
These materials can also be used in personal protective equipment which includes all the clothing that can be worn to prevent any injury or illness due to the exposure to radiation.
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